Method of preparing wood-pulp.



' dissolving1 or C CARL BACHE-WG, OF BERLIN, N E'i HAEII'ESHRE, ASSGNGROF @NE-HALE T0 BERLEN MLLS COMPANY, OF PGRTLAND, MAENE, A CRPQMlON 03?MEN'E.

METHOD F REPARXN@ WD-ULP.

No Brewing.

To all ywil/0m it may. Concern Be it known that l, CARL Brione-lwoo, scitizen of the United States, residing at Ben lin, in the county of Coosand, State of N ew Hampshire, have invented an improvement 'in Methodsof repsring l/vood-Pullo, or

which the following' is e specification.

rlhis invention relates to e process for treating wood for theproduction ofi s white ,Ground wood pulp for paper, which een oe usedwithout ndnii'xture with it of any suliite, und newspaper of e goedquality produced, or it may ,he mixed with suliite or used as n mixer ino strong wrapping paper, Manilay saper or heg-peper, und is intended esan n provenient upon the process forming the subject-metter of Lettersl3ntnt $913,679, dated lvnreli 2, 1909.,

present inrention consists in eontlning the :orin of blocks, in e dithewood, in i gestel, then withdrawing the air :from theni, therebyproducing in the digester u ysouuin, or more strictiy speaking, apartiel Vacuum, then pressing in sulrurous ges, such es suiur dioXid tohlenoh the outer portions oi the `loloelrs, und to soften hut otdissolve. or destroy the ligninous in JJer; then injecting water endcooking the mess, which results in further softening hut lestroying theligninous instter which is contained in the outer portion of the blocks;or in lieu of inliecting water injecting solution o' sodium ehlorid(NaCl) and cooking the mess, which results in still further softening1out not dissolving or destroying the ligninous matter which iscontained in the outer portions oi the blocks; or, in lieu of injeetinge solu tion or sodiurn clilorid, injecting s bisultite liquor andcooking the mass, which results in 'producing s high grade oir pulp, butthe ligninous instter will not he saved to the saine extent es when ssolution ot sodium4 chlorid or water is employed, end the yield will hecorrespondingly iess; or in lieu thereof injecting s bisulte liquor andcookinff the mass tor e,k few hours, ssy tour or five hours, thenblowing oit the loisulite liquor and injectings. sodium chlorid solutionand further cooking themass, which results in a larger yield than whencooking the mass in a loisulte liquor sloneiend the ber is strong andIthe color white; and then grinding the blocks in any usuel or suitablemanner, thereloy producing s niiir- Specicaton of Letters vatent.

Fetented Inn 25, Minid,

Application filed leoember 3.4, 1912. Serial lo. 738,705.

ture oi treated end untreated iiloers. The pulp thus produced is welladapted as s sulo stitute or s mixture of ground wood end suit/ite.

withdrawing the air rointhe oloelrs f the bleaching softening gas willlo@ The solution or may oe of any degree ot c Atration and nertile

when employed the w e cooked for soy sin or seven hours, whi l sn3ieient, although it longer or shorter period of @i to the quality orpulp whitA is desired to produce iner quality or wiil oe produced ley slonfer eooliin or the rnsssu d' orid esso-,

oiuted with sulfur dio e, lnr. tenipernture ne niuss is heinJ suits isli'- t ation oi"- e salt,

oieeening,

siding so port ons of the discoloration the inner i the loloelis,so-thet seid inner oortions ore of s naturel color or even ter, insteadorn being derlrened es lies heretofore heen the case in ull processesknown to ine where the outer portions o the blocks are treeted and tl einner portions thereof ere left treated, and es e result s high grade otmuy he produced es contrasted with e low grade. 'lr-he *power requiredto grind the blocks thus treated is rnueh less thon is usually requiredto grind the blocks of wood und the Ytiene required for the grindingoperation is also less,

ll claimti. The herein described process of preparing wood pulp forpeper whieh consists in eonifiningga the wood, in the orn of blocks, ine digester, withdrawing the sir from them, and while the sir is windrswn from them pressing into thern ior substantiel depth s gas bywhich outer -portions thereoie are hlesched and the ligninous niettersoftened but not destroyed, then injeeting e pulp-forming liquor andcooking the mass, whereupon a, salt is formed by the essociution of thepulp forming liquor and theehlorid lill@ gas which aids in softening andbleaching and prevents discoloration of the fibers at the inner portionsof the blocks and then grinding up the blocks.

2. The herein described process Aof preparing wood pulp for paper` whichconsists in confining the wood, in the form of blocks, in a digester,withdrawing the air from them, and while the air is withdrawn from thempressing into them for a substantial depth sulfur dioXid by which theouter portions thereof are bleached and the ligninous matter softenedbut not destroyed, then injecting a pulp-forming liquor and cooking themass, whereupon a salt is formed by the association of the pulp formingliquor and sulfur dioXid which aids in softening and bleaching, andprevents discoloration of the fibers at the inner portions of theblocksand then grinding up the blocks.

3. The herein described process of preparing wood pulp for paper whichconsists in confining the wood, in the form of blocks, in a digester,withdrawing the air from them, and while the air is withdrawn from thempressing into them for a substantial depth a gas by which the outerportions thereof are bleached and the ligninous matter softened but notdestroyed, ,then injecting a solution of sodium chlorid and cooking themass, whereupon a salt is formed by the association of the sodiumchlorid and gas which aids in softening and bleaching,

and' prevents discoloration of the fibers at' the inner portions of theblocks and then grindingup the blocks.

4. rThe lherein described process of preparing wood pulp for paper whichconsists in confining the wood, in the form of blocks, in a digester,withdrawing the air from them, and while the air is withdrawn from thempressing into them for a substantial depth sulfur dioXid by whichthe-outer portions thereof are bleached and the ligninous mattersoftened but not destroyed, then injecting a solution of sodium chloridand cooking the mass, whereupon a salt is formed by the association ofthe sodium chlorid and sulfur dioXid which aids in softening andbleaching, and prevents discoloration of the fibers* at the innerportions of the blocks and then grinding up the blocks.

5. The herein described process of preparing wood pulp for paper whichconsists in confining the wood in the form of blocks in a digester,pressing into them for a substantial depth a gas by -which'the outerportions thereof are bleached and the ligninous matter softened but notdestroyed, then injecting a pulp-forming element and cooking the mass,said pulp-forming element by association with the gas when the mass isheated to a high temperature forming a salt which prevents discolorationof the fibers at the inner portions of the blocks and then grinding upthe blocks.

6. The herein described process ofV preparing wood pulp for paper whichconsists in confining the wood in the form of blocks in a digester,pressing into them for a substantial depth sulfur vdioXid by which theouter portions thereof are bleached and the ligninous matter softenedbut not destroyed, then injecting a solution of sodium chlorid andcooking the mass, whereupon a salt is formed by the association of thesodium chlorid and sulfur dioXid which prevents discoloration of thefibers at the inner portions ofthe blocks and then grinding up theblocks.

7. The herein described process of preparing -wood pulp for paper whichconsists in confining the wood, in the form of blocks, in a digester,withdrawing the air from them, pressing into them for substantial deptha gas by which the outer portions thereof are bleached and the ligninousmatter softened but not destroyed, then injecting a bisulfite li uor andcooking the mass, then blowing o lthe bisulfte liquor, then injecting asodium chlorid solution and cooking the mass and then grinding up theblocks.

In testimony whereof, l have signed my name to this specification, inthe presence of two subscribing witnesses.

CARL BAoriE-WG.

Witnesses:

WM. H. PAINE, E. McComi'r MACY.

Itis hereby certified that the name of the petentee in Letters PatentNo. 1,169,597,

granted Jennary25, 1916, for an improvement in Methods of PreparingWood- Pulp, Was erroneously Written and printed as Carl Bache-Wg,Whereas sein name should have been Written and printed es Carl BackeWfig; and that the seid Letters Patent should be reed with thiscorrection therein thet the seme may conform to the record of the casein the Patent @Hice Signed und sealed this 3rd day of July, A. D., 1917.

' r. W. H. CLAY,

Acting Commissioner of Pater/'18s.,

[SEAL]

